they cant? if that was the case you would have some serious problems with disease come spring due to the winter die offs! You would be suprised how well they can survive! Also feeding wild critters isnt something to take lightly. Its a responsibility to the extent of working on a farm...feeding 3 times a day, milking 3 times a day, not to mention the daily activities that must be done...NO play time!! No private time! Those deer will become dependent on you.....you let them down...they die!